The present invention relates to a method of forming an image, and to a product having an image formed thereon. In particular, this invention provides an enhanced security image.
WO96/30215 describes a method of forming an image on a surface of a card, and in particular the formation of a security card. In general terms, a plastics card is provided on to which an image and other data or markers is printed for example using a dye sublimation or dye diffusion printing process. Once printed, the image on the card is protect by laying down a thin transparent plastic costing. The plastic coating (hereinafter called xe2x80x9covercoatxe2x80x9d) is deposited by thermal transfer printing. Security images can also be formed in the overcoat by overheating portions of it, thereby changing the optical properties over the overcoat. In general, the overheated portions of the film take on a less glossy (i.e. matt or satin), appearance. Thus additional images confirming the authenticity of the card can be formed in the transparent layer, with the printed portion of the card being visible therethrough. The security images can be easily seen when the card is illuminated by a unidirectional light source, but are less clear when viewed in diffuse lights
According to a first aspect of the present invention, them is provided a method of forming an image, comprising providing a layer of plastics material over a substrate, the substrate having at least one reflective region thereon, and selectively altering the optical properties of portions of the plastics material so as to form an image therein.
It is thus possible to provide an improved security card. The applicant has discovered the security markings become much more visible, even in diffuse light, when printed over a reflective region.
Advantageously the reflective region comprises a reflective film, such as a metallic film, or a film exhibiting mirror like reflection properties. The metal film may be printed on to the substrate. Thus a metal film may be provided on blank card stock at the time of manufacture of security cards. Alternatively, the reflective film may be printed onto the card as part of the card printing process. Thus, for example, the metal film may be provided on a carrier film and be brought into contact with the substrate at a printing station in order to transfer the metal film to the substrate.
Preferably the layer of plastics film is provided on a carrier film. The carrier film may be brought into contact with the substrate at a printer having a plurality of heater elements. The heater elements may be energised in order to thermally transfer the plastics material from the carrier film to the substrate.
The heater elements may be energised at a plurality of energy levels in order to vary the thickness of the plastics film transferred. The varying thickness thereby resulting in a variable appearance of the film.
Alternatively, the heater elements may be energised to a first value in order to transfer the entirety of the thickness of the plastics film to the substrate, and selective ones of the heater elements may be energised to a second value in order to overwork or overheat the deposited film, thereby varying its optical properties. Thus the appearance of the overworked areas may be matt or satin, when compared to the other portions of the film.
The security image may be repeatedly printed across the card in a repeat and step like manner. However, advantageously at least one of the images overlies the reflective region.
Advantageously the print instructions for the security image are stored in a memory device. The memory device may, for example, be implemented in the form of a removable memory card, a dongle, a smart card or other equivalent removable memory element. The security image may be held in an encrypted form and local processing may also be provided such that the encrypted image cannot be accessed without a suitable key. The key may, for example, be available to authorize users on a time limited fashion such that once the key expires the security image can no longer be printed. Replacement keys may be obtained via a telecommunications network, for example over the Internet, or by distribution of suitably encoded disks or by passwords. Alternatively the printer itself may act as the key to read the data from the memory element.
The printer may have a data processor arranged such that the negotiates with the memory element to obtain the security image therefrom. The security image may be in an encrypted form. The encrypted form may differ every time the image is read from the memory device. The data processor in the printer is arranged to decrypt the image.
According to a second aspect of the present invention, there is provided a security product printed in accordance with the first aspect.
Advantageously the security product is one of a bank card, a credit card, and a security card.
It is thus possible to provide a security card comprising a plastics substrate bearing on at least one portion thereof a reflective element, and a plastics layer deposited over the substrate and the reflective element, the optical properties of the plastics layer being altered in at least the region overlying the reflective element in order to form a visible marking therein.
Advantageously the substrate is printed with identification details, such as words, pictures or other indicia. The printing may be performed by dye sublimation printing. Following the printing step, the protective layer is then deposited on the card, with the simultaneous formation of security images in the protective layer. The protective layer may be applied to the card by thermal transfer.